For which category has the EPA established both concentration- and mass-based standards?

The Environmental Protection Agency (EPA) has established both concentration- and mass-based standards specifically for pulp, paper, and paperboard manufacturing. This reflects the industry's unique characteristics and its potential environmental impact due to the various pollutants generated during production processes.

Concentration-based standards focus on limiting the allowable concentration of specific pollutants in wastewater, ensuring that treated effluent discharged into the environment meets safety benchmarks. Meanwhile, mass-based standards take into account the total quantity of pollutants being discharged over a specified time frame, which emphasizes the overall load that enters waterways.

The establishment of both types of standards for this sector aims to promote more effective pollution control strategies by addressing both the efficiency of treatment processes (concentration) and the total impact on receiving waters (mass). This dual approach is crucial in helping manage the environmental effects associated with industrial discharges from pulp, paper, and paperboard manufacturing, ultimately leading to improved water quality.